Per il fine settimana resto a casa.

Here per means for in a time-related sense: for the weekend.

So Per il fine settimana means something like:

• for the weekend
• over the weekend
  depending on context

In Italian, per is often used to indicate a period of time connected to a plan or intention.

Italian often uses the definite article with time expressions more than English does.

So:

• il fine settimana = the weekend
• per il fine settimana = for the weekend

In everyday speech, you may also hear nel fine settimana, durante il fine settimana, or simply questo fine settimana, depending on the exact meaning.

Also, many speakers just say weekend:

• Per il weekend resto a casa.

That is very common too.

Literally, fine settimana means end of the week:

• fine = end
• settimana = week

But as a fixed expression, it means weekend.

So even though the literal parts are transparent, you should learn fine settimana as one time expression.

Resto comes from restare, which means to stay or to remain.

So:

• resto a casa = I stay home / I’m staying home

If you used sono a casa, that would mean:

• I am at home

That describes your location, but it does not emphasize the idea of staying there.

So in this sentence, resto is the natural choice because the idea is not just where you are, but that you are remaining at home for that period.

Yes. Rimango a casa is also correct.

Both restare and rimanere can mean to stay / remain. In many contexts they are interchangeable.

So these are both fine:

• Per il fine settimana resto a casa.
• Per il fine settimana rimango a casa.

There can be slight stylistic or regional preferences, but for a learner, both are good and natural.

Italian usually leaves out subject pronouns when the verb form already makes the subject clear.

Here, resto clearly means I stay, so io is not necessary.

• resto = I stay
• io resto = I stay (with extra emphasis)

You would add io only if you want contrast or emphasis, for example:

• Io resto a casa, ma loro escono.
  I’m staying home, but they’re going out.

A casa is a fixed Italian expression meaning at home or home.

So:

• sono a casa = I am at home
• resto a casa = I stay home

Italian does not usually use the article here.
If you said alla casa, it would usually mean to the house, referring to a specific building, not the idea of home.

So a casa is the idiomatic form you should learn.

Yes, resto is grammatically the present tense.

But in Italian, just like in English, the present tense is often used to talk about a planned future action, especially when the time is clear from context.

Here the time is given by Per il fine settimana, so resto a casa can naturally mean:

• I’m staying home for the weekend
• I’ll stay home for the weekend

This is very common and natural Italian.

Yes. Italian word order is flexible, although some versions sound more neutral than others.

The original sentence:

• Per il fine settimana resto a casa.

is perfectly natural.

You could also say:

• Resto a casa per il fine settimana.

This may sound slightly more straightforward to English speakers because the time phrase comes later.

Both are correct.
Putting Per il fine settimana first can give a little more emphasis to the time frame.

Both exist, but weekend is extremely common in everyday Italian.

So you may hear:

• Per il weekend resto a casa.

more often in casual speech.

Fine settimana is completely correct and understood by everyone, but it can sound a bit more formal, careful, or textbook-like depending on the speaker and context.

So as a learner, it is good to know both:

• fine settimana = more purely Italian expression
• weekend = very common everyday choice